1. Field of the Invention
This invention generally relates to a linear motor drive unit compact in size and in particular to a linear motor drive unit including the basic structure of a linear motion rolling contact guide unit.
2. Description of the Prior Art
A linear motion rolling contact guide unit is well known in the art, and it generally includes a rail extending over a length, a slider and a plurality of rolling members, such as balls or rollers, interposed between the rail and the slider so that a relative linear motion may be provided between the rail and the slider. Such a linear motion rolling contact guide unit is typically combined with a linear motor as a driving source for driving to move the slider relative to the rail. Such a linear motor is typically provided separately from and connected to the slider of the linear motion rolling contact guide unit through an arm. Such a linear motor typically includes a structure which is obtained by developing the structure of a rotary motor, including a rotor, a stator and an air gap therebetween, along a straight line, and it is a device for converting electrical energy directly to linear motion energy.
However, such a prior art linear motor drive unit, which is a combination of a linear motion rolling contact guide unit and a linear motor, tends to be bulky in size, and, thus, its applications have been rather limited. In addition, since the linear motor is typically connected to the slider of the linear motion rolling contact guide unit through an elongated arm, the prior art linear motor drive unit tends to be inferior in rigidity.